Compositing Layer update for OffscreenCanvas resize

content/browser/renderer_host/offscreen_canvas_compositor_frame_sink.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/renderer_host/offscreen_canvas_compositor_frame_sink.h"
 
 #include "cc/surfaces/surface.h"
 #include "cc/surfaces/surface_manager.h"
 #include "content/browser/compositor/surface_utils.h"
+#include "content/browser/renderer_host/offscreen_canvas_surface_impl.h"
+#include "content/browser/renderer_host/offscreen_canvas_surface_manager.h"
 #include "mojo/public/cpp/bindings/strong_binding.h"
 
 namespace content {
 
 OffscreenCanvasCompositorFrameSink::OffscreenCanvasCompositorFrameSink(
     const cc::SurfaceId& surface_id,
     cc::mojom::MojoCompositorFrameSinkClientPtr client)
     : surface_id_(surface_id), client_(std::move(client)) {
   cc::SurfaceManager* manager = GetSurfaceManager();
   surface_factory_ = base::MakeUnique<cc::SurfaceFactory>(
       surface_id_.frame_sink_id(), manager, this);
   manager->RegisterFrameSinkId(surface_id_.frame_sink_id());
-  surface_factory_->Create(surface_id_.local_frame_id());
 }
 
 OffscreenCanvasCompositorFrameSink::~OffscreenCanvasCompositorFrameSink() {
   cc::SurfaceManager* manager = GetSurfaceManager();
   if (!manager) {
     // Inform SurfaceFactory that SurfaceManager's no longer alive to
     // avoid its destruction error.
     surface_factory_->DidDestroySurfaceManager();
   } else {
     manager->InvalidateFrameSinkId(surface_id_.frame_sink_id());
   }
   surface_factory_->Destroy(surface_id_.local_frame_id());
 }
 
 // static
 void OffscreenCanvasCompositorFrameSink::Create(
     const cc::SurfaceId& surface_id,
     cc::mojom::MojoCompositorFrameSinkClientPtr client,
     cc::mojom::MojoCompositorFrameSinkRequest request) {
   mojo::MakeStrongBinding(base::MakeUnique<OffscreenCanvasCompositorFrameSink>(
                               surface_id, std::move(client)),
                           std::move(request));
 }
 
 void OffscreenCanvasCompositorFrameSink::SubmitCompositorFrame(
     cc::CompositorFrame frame) {
+  cc::RenderPass* root_pass = frame.render_pass_list.back().get();
+  gfx::Size surface_size = root_pass->output_rect.size();
+
+  if (!GetSurfaceManager()->GetSurfaceForId(surface_id_)) {

[Fady Samuel, 2016/11/22 16:04:09]

I hate to be overly nitpicky but this flow doesn't match other
CompositorFrameSinks. In the interest of producing a unified API, please try to
get to that state.

SurfaceIdAllocator should be owned by CompositorFrameSink.

See GpuCompositorFrameSink::SubmitCompositorFrame. Please try to match that
code.

OffscreenCanvasCompositorFrameSink should not know about
OffscreenCanvasSurfaceImpl.

+    // If this is the first commit, surface_id_ is not used to create a new
+    // Surface yet.
+    surface_factory_->Create(surface_id_.local_frame_id());
+    current_surface_size_ = surface_size;
+  } else if (surface_size != current_surface_size_) {
+    // If this is not the first commit, we check whether there is a resize
+    // since the previous commit.
+    OffscreenCanvasSurfaceImpl* surface_impl =
+        OffscreenCanvasSurfaceManager::GetInstance()->GetSurfaceInstance(
+            surface_id_.frame_sink_id());
+    if (!surface_impl) {
+      // We may end up here when the HTMLCanvasElement-
+      // OffscreenCanvasSurfaceImpl connection is torn down and the
+      // OffscreenCanvas-CompositorFrameSink connection is still working. In
+      // this case, we ignore the commit() because it is meaningless to
+      // process a compositor frame when there is no placeholder canvas for
+      // this OffscreenCanvas.
+      LOG(ERROR) << "OffscreenCanvas is submitting frame when its place holder"
+                 << " canvas's browser service-end does no longer exist.";
+      return;
+    }
+
+    cc::LocalFrameId new_local_frame_id = surface_impl->GenerateLocalFrameId();
+    surface_factory_->Destroy(surface_id_.local_frame_id());
+    surface_id_ =
+        cc::SurfaceId(surface_id_.frame_sink_id(), new_local_frame_id);
+    surface_factory_->Create(surface_id_.local_frame_id());
+    current_surface_size_ = surface_size;
+    surface_impl->OnSurfaceSizeChanged(surface_id_, current_surface_size_);
+  }
+
   ++ack_pending_count_;
   surface_factory_->SubmitCompositorFrame(
       surface_id_.local_frame_id(), std::move(frame),
       base::Bind(
           &OffscreenCanvasCompositorFrameSink::DidReceiveCompositorFrameAck,
           base::Unretained(this)));
 }
 
 void OffscreenCanvasCompositorFrameSink::SetNeedsBeginFrame(
     bool needs_begin_frame) {
@@ skipping 27 matching lines @@
   client_->DidReceiveCompositorFrameAck();
   DCHECK_GT(ack_pending_count_, 0);
   if (!surface_returned_resources_.empty()) {
     client_->ReclaimResources(surface_returned_resources_);
     surface_returned_resources_.clear();
   }
   ack_pending_count_--;
 }
 
 }  // namespace content